Analytical Fit to the Luminosity Distance for Flat Cosmologies with a Cosmological Constant

1999 ◽  
Vol 120 (1) ◽  
pp. 49-50 ◽  
Author(s):  
Ue‐Li Pen
Keyword(s):  
Cosmological Constant ◽  
Luminosity Distance

scholarly journals The effect of the cosmological constant on a quadrupole signal in the linearized approximation

2018 ◽  
Vol 27 (02) ◽  
pp. 1850004 ◽  
Author(s):  
László Ábel Somlai ◽  
Mátyás Vasúth
Keyword(s):  
General Relativity ◽  
Cosmological Constant ◽  
Gravitational Wave ◽  
Equations Of Motion ◽  
Luminosity Distance ◽  
Background Term ◽  
Self Consistent ◽  
Linearized Theory

In this study the effects of a nonzero cosmological constant [Formula: see text] on a quadrupole gravitational wave (GW) signal are analyzed. The linearized approximation of general relativity was used, so the perturbed metric can be written as the sum of [Formula: see text] GWs and [Formula: see text] background term, originated from [Formula: see text]. The [Formula: see text] term was also included in this study. To derive physically relevant consequences of [Formula: see text] comoving coordinates are used. In these coordinates, the equations of motion (EoMs) are not self-consistent so the result of the linearized theory has to be transformed to the FRW frame. The luminosity distance and the same order of the magnitude of frequency in accordance with the detected GWs were used to demonstrate the effects of the cosmological constant.

Cosmological constant

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Vacuum Fluctuations ◽  
Present Epoch ◽  
Modify Gravity ◽  
Expansion Of The Universe ◽  
The Universe

The contribution of vacuum fluctuations to the cosmological constant is reconsidered studying the dependence on the used regularisation scheme. Then alternative explanations for the observed accelerated expansion of the universe in the present epoch are introduced which either modify gravity or add a new component of matter, dubbed dark energy. The chapter closes with some comments on attempts to quantise gravity.

scholarly journals Neutral signature gauged supergravity solutions

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
J. Gutowski ◽  
W. A. Sabra
Keyword(s):  
Cosmological Constant ◽  
Geometric Structure ◽  
Base Space ◽  
Killing Spinor ◽  
Positive Cosmological Constant ◽  
3 Dimensional

Abstract We classify all supersymmetric solutions of minimal D = 4 gauged supergravity with (2) signature and a positive cosmological constant which admit exactly one Killing spinor. This classification produces a geometric structure which is more general than that found for previous classifications of N = 2 supersymmetric solutions of this theory. We illustrate how the N = 2 solutions which consist of a fibration over a 3-dimensional Lorentzian Gauduchon-Tod base space can be written in terms of this more generic geometric structure.

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